One of the main problems in developing edible coatings is theirnegative effects on gas permeation, and consequent modificationof the internal atmosphere of the fruit, which results in accumula-tion of CO2and stimulation of anaerobic respiration. In the presentstudy, we found that the commercial wax and the CMC/chitosanbilayer coating significantly increased CO2levels in the internalatmospheres of ‘Or’ mandarins and ‘Star Ruby’ grapefruit, but hadno significant effects on CO2levels in ‘Mor’ mandarins and ‘Navel’orange (Fig. 3A). In all cases, CO2levels in the internal atmospheresof control and coated fruit never exceeded 3.5% (Fig. 3A).